University Housing and Dining policies and rules pertaining to students can be found here:
Standards of Student Behavior

1. Visitation Policy in the Residence Halls. Non-resident students have the privilege of entering University residence halls as long as they observe Residence Hall rules at all times. Violation of residence hall regulations constitutes a breach of Regulation 16 of the Code of Student Life. Housing regulations are posted on line at http://housing.uiowa.edu/res-hall-guidebook/index.html. Non-residents are welcome in the dining service, information technology centers (ITC), and main lounge areas. With the permission of a resident of the floor, a student who resides off-campus may enter a residential floor area as a guest of the resident host. A non-resident student directed to leave the building by a staff member is expected to comply with the directive. Non-residents may not engage in door-to-door commercial solicitation in the residence halls.
2. Security. The doors to most residence halls are locked from midnight to 6:00 a.m. every night for security purposes. Entry thereafter may be restricted or controlled in accordance with residence hall policy. Non-resident students who fail to observe security restrictions are in violation of the Regulations 7 and 16 of the Code of Student Life.
3. Parietal Rule. The University’s parietal rule, which required unmarried freshmen and sophomores to reside in University residence halls, has been suspended by the State Board of Regents. The parietal rule shall be automatically reinstated unless the Board of Regents takes action to extend the period of suspension.
4. No Contract Release. Students living in residence halls during the first semester of an academic year are not released from their academic year contract for the second semester if the student is enrolled for classes.